/*
 * Header for use in defining a given L4 protocol for connection tracking.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *	- generalized L3 protocol dependent part.
 *
 * Derived from include/linux/netfiter_ipv4/ip_conntrack_protcol.h
 */

#ifndef _NF_CONNTRACK_L4PROTO_H
#define _NF_CONNTRACK_L4PROTO_H
#include <linux/netlink.h>
#include <net/netlink.h>
#include <net/netfilter/nf_conntrack.h>

struct seq_file;

struct nf_conntrack_l4proto {
	/* L3 Protocol number. */
	u_int16_t l3proto;

	/* L4 Protocol number. */
	u_int8_t l4proto;

	/* Try to fill in the third arg: dataoff is offset past network protocol
	   hdr.  Return true if possible. */
	 bool(*pkt_to_tuple) (const struct sk_buff * skb, unsigned int dataoff,
			      struct nf_conntrack_tuple * tuple);

	/* Invert the per-proto part of the tuple: ie. turn xmit into reply.
	 * Some packets can't be inverted: return 0 in that case.
	 */
	 bool(*invert_tuple) (struct nf_conntrack_tuple * inverse,
			      const struct nf_conntrack_tuple * orig);

	/* Returns verdict for packet, or -1 for invalid. */
	int (*packet) (struct nf_conn * ct,
		       const struct sk_buff * skb,
		       unsigned int dataoff,
		       enum ip_conntrack_info ctinfo,
		       u_int8_t pf, unsigned int hooknum);

	/* Called when a new connection for this protocol found;
	 * returns TRUE if it's OK.  If so, packet() called next. */
	 bool(*new) (struct nf_conn * ct, const struct sk_buff * skb,
		     unsigned int dataoff);

	/* Called when a conntrack entry is destroyed */
	void (*destroy) (struct nf_conn * ct);

	int (*error) (struct net * net, struct sk_buff * skb,
		      unsigned int dataoff, enum ip_conntrack_info * ctinfo,
		      u_int8_t pf, unsigned int hooknum);

	/* Print out the per-protocol part of the tuple. Return like seq_* */
	int (*print_tuple) (struct seq_file * s,
			    const struct nf_conntrack_tuple *);

	/* Print out the private part of the conntrack. */
	int (*print_conntrack) (struct seq_file * s, const struct nf_conn *);

	/* convert protoinfo to nfnetink attributes */
	int (*to_nlattr) (struct sk_buff * skb, struct nlattr * nla,
			  const struct nf_conn * ct);

	/* convert nfnetlink attributes to protoinfo */
	int (*from_nlattr) (struct nlattr * tb[], struct nf_conn * ct);

	int (*tuple_to_nlattr) (struct sk_buff * skb,
				const struct nf_conntrack_tuple * t);
	int (*nlattr_to_tuple) (struct nlattr * tb[],
				struct nf_conntrack_tuple * t);
	const struct nla_policy *nla_policy;

#ifdef CONFIG_SYSCTL
	struct ctl_table_header **ctl_table_header;
	struct ctl_table *ctl_table;
	unsigned int *ctl_table_users;
#ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
	struct ctl_table_header *ctl_compat_table_header;
	struct ctl_table *ctl_compat_table;
#endif
#endif
	/* Protocol name */
	const char *name;

	/* Module (if any) which this is connected to. */
	struct module *me;
};

/* Existing built-in protocols */
extern struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp6;
extern struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4;
extern struct nf_conntrack_l4proto nf_conntrack_l4proto_udp6;
extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;

#define MAX_NF_CT_PROTO 256

extern struct nf_conntrack_l4proto *__nf_ct_l4proto_find(u_int16_t l3proto,
							 u_int8_t l4proto);

extern struct nf_conntrack_l4proto *nf_ct_l4proto_find_get(u_int16_t l3proto,
							   u_int8_t protocol);

extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);

/* Protocol registration. */
extern int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *proto);
extern void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *proto);

/* Generic netlink helpers */
extern int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
				      const struct nf_conntrack_tuple *tuple);
extern int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
				      struct nf_conntrack_tuple *t);
extern const struct nla_policy nf_ct_port_nla_policy[];

#ifdef CONFIG_SYSCTL
#ifdef DEBUG_INVALID_PACKETS
#define LOG_INVALID(net, proto)				\
	((net)->ct.sysctl_log_invalid == (proto) ||	\
	 (net)->ct.sysctl_log_invalid == IPPROTO_RAW)
#else
#define LOG_INVALID(net, proto)				\
	(((net)->ct.sysctl_log_invalid == (proto) ||	\
	  (net)->ct.sysctl_log_invalid == IPPROTO_RAW)	\
	 && net_ratelimit())
#endif
#else
static inline int LOG_INVALID(struct net *net, int proto)
{
	return 0;
}
#endif /* CONFIG_SYSCTL */

#endif /*_NF_CONNTRACK_PROTOCOL_H*/
